When a network is configured in an initial cell design of a cellular wireless communication system, coverage holes are generated due to surroundings or regional features such as buildings. The coverage hole is an area within a radio coverage of a wireless system, in which a radio frequency (RF) signal level is below a preset threshold. The coverage hole is usually caused by physical obstructions such as buildings, trees, tunnels, and indoor parking garages.
To address the coverage hole, current cellular wireless communication systems by installing repeaters. Disadvantageously, repeaters cause performance degradation in noise amplification. In response to this, a relay system is suggested to decode and forward a signal from a base station (BS), beyond mere signal amplification. Research is conducted on the relay system for the sake of throughput enhancement and coverage extension of the cellular wireless communication system. The Institute of Electrical and Electronics Engineers (IEEE) 802.16j is standardizing the relay system for its practical use. Using a relay station (RS), deployment and maintenance costs can be reduced, and the performance can be improved compared to a conventional single-hop system.
However, the current RS operates based on a half duplex scheme. Communications using the half-duplex RS utilize radio resources between the BS and the RS and radio resources between the RS and a terminal. In this case, the increased resource consumption is quite inefficient compared to the single-hop system (the system without RSs).